added specializing error "Variable initializer is redundant" for unused-vars analysis

compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetFlowInformationProvider.java

@@ -16,6 +16,7 @@ import org.jetbrains.jet.lang.psi.*;
 import org.jetbrains.jet.lang.resolve.BindingContext;
 import org.jetbrains.jet.lang.resolve.BindingContextUtils;
 import org.jetbrains.jet.lang.resolve.BindingTrace;
+import org.jetbrains.jet.lang.resolve.DescriptorUtils;
 import org.jetbrains.jet.lang.types.JetStandardClasses;
 import org.jetbrains.jet.lang.types.JetType;
 import org.jetbrains.jet.lexer.JetTokens;
@@ -354,8 +355,11 @@ public class JetFlowInformationProvider {
             return true;
         }
 
-        JetClassOrObject propertyClassOrObject = PsiTreeUtil.getParentOfType(property, JetClassOrObject.class);
+        JetNamedDeclaration parentDeclaration = PsiTreeUtil.getParentOfType(element, JetNamedDeclaration.class);
-        if (propertyClassOrObject == null || !PsiTreeUtil.isAncestor(propertyClassOrObject, element, false)) {
+        DeclarationDescriptor declarationDescriptor = trace.get(BindingContext.DECLARATION_TO_DESCRIPTOR, parentDeclaration);
+        assert declarationDescriptor != null;
+        ClassDescriptor variableClass = DescriptorUtils.getParentOfType(variableDescriptor, ClassDescriptor.class);
+        if (variableClass == null || !DescriptorUtils.isAncestor(variableClass, declarationDescriptor, false)) {
             trace.report(Errors.INACCESSIBLE_BACKING_FIELD.on(element));
             return true;
         }
@@ -482,11 +486,7 @@ public class JetFlowInformationProvider {
         assert pseudocode != null;
         JetControlFlowGraphTraverser<Map<VariableDescriptor, VariableStatus>> traverser = JetControlFlowGraphTraverser.create(pseudocode, true, false);
         final Collection<VariableDescriptor> declaredVariables = collectDeclaredVariables(subroutine);        
-        Collection<VariableDescriptor> usedVariables = collectUsedVariables(pseudocode);
         Map<VariableDescriptor, VariableStatus> sinkInstructionData = Maps.newHashMap();
-        for (VariableDescriptor usedVariable : usedVariables) {
-            sinkInstructionData.put(usedVariable, VariableStatus.UNUSED);
-        }
         traverser.collectInformationFromInstructionGraph(new JetControlFlowGraphTraverser.InstructionDataMergeStrategy<Map<VariableDescriptor, VariableStatus>>() {
             @Override
             public Pair<Map<VariableDescriptor, VariableStatus>, Map<VariableDescriptor, VariableStatus>> execute(Instruction instruction, @NotNull Collection<Map<VariableDescriptor, VariableStatus>> incomingEdgesData) {
@@ -505,7 +505,17 @@ public class JetFlowInformationProvider {
                         exitResult.put(variableDescriptor, VariableStatus.READ);
                     }
                     else if (instruction instanceof WriteValueInstruction) {
-                        exitResult.put(variableDescriptor, VariableStatus.WRITTEN);
+                        VariableStatus variableStatus = enterResult.get(variableDescriptor);
+                        if (variableStatus == null) variableStatus = VariableStatus.UNUSED;
+                        switch(variableStatus) {
+                            case UNUSED:
+                            case ONLY_WRITTEN:
+                                exitResult.put(variableDescriptor, VariableStatus.ONLY_WRITTEN);
+                                break;
+                            case WRITTEN:
+                            case READ:
+                                exitResult.put(variableDescriptor, VariableStatus.WRITTEN);
+                        }
                     }
                 }
                 return new Pair<Map<VariableDescriptor, VariableStatus>, Map<VariableDescriptor, VariableStatus>>(enterResult, exitResult);
@@ -516,13 +526,12 @@ public class JetFlowInformationProvider {
             public void execute(Instruction instruction, @Nullable Map<VariableDescriptor, VariableStatus> enterData, @Nullable Map<VariableDescriptor, VariableStatus> exitData) {
                 assert enterData != null && exitData != null;
                 VariableDescriptor variableDescriptor = extractVariableDescriptorIfAny(instruction, false);
-                if (variableDescriptor == null || !declaredVariables.contains(variableDescriptor)) return;
+                if (variableDescriptor == null || !declaredVariables.contains(variableDescriptor) ||
-                PsiElement variableDeclarationElement = trace.get(BindingContext.DESCRIPTOR_TO_DECLARATION, variableDescriptor);
+                    !DescriptorUtils.isLocal(variableDescriptor.getContainingDeclaration(), variableDescriptor)) return;
-                assert variableDeclarationElement instanceof JetDeclaration;
+                VariableStatus variableStatus = enterData.get(variableDescriptor);
-                if (!JetPsiUtil.isLocal((JetDeclaration) variableDeclarationElement)) return;
                 if (instruction instanceof WriteValueInstruction) {
                     JetElement element = ((WriteValueInstruction) instruction).getElement();
-                    if (enterData.get(variableDescriptor) == VariableStatus.WRITTEN || enterData.get(variableDescriptor) == VariableStatus.UNUSED) {
+                    if (variableStatus != VariableStatus.READ) {
                         if (element instanceof JetBinaryExpression && ((JetBinaryExpression) element).getOperationToken() == JetTokens.EQ) {
                             JetExpression right = ((JetBinaryExpression) element).getRight();
                             if (right != null) {
@@ -542,7 +551,7 @@ public class JetFlowInformationProvider {
                     if (element instanceof JetNamedDeclaration) {
                         PsiElement nameIdentifier = ((JetNamedDeclaration) element).getNameIdentifier();
                         PsiElement elementToMark = nameIdentifier != null ? nameIdentifier : element;
-                        if (enterData.get(variableDescriptor) == VariableStatus.UNUSED) {
+                        if (variableStatus == null || variableStatus == VariableStatus.UNUSED) {
                             if (element instanceof JetProperty) {
                                 trace.report(Errors.UNUSED_VARIABLE.on((JetProperty) element, elementToMark, variableDescriptor));
                             }
@@ -559,9 +568,15 @@ public class JetFlowInformationProvider {
                                 }
                             }
                         }
-                        else if (enterData.get(variableDescriptor) == VariableStatus.WRITTEN && element instanceof JetProperty) {
+                        else if (variableStatus == VariableStatus.ONLY_WRITTEN && element instanceof JetProperty) {
                             trace.report(Errors.ASSIGNED_BUT_NEVER_ACCESSED_VARIABLE.on((JetNamedDeclaration) element, elementToMark, variableDescriptor));
                         }
+                        else if (variableStatus == VariableStatus.WRITTEN && element instanceof JetProperty) {
+                            JetExpression initializer = ((JetProperty) element).getInitializer();
+                            if (initializer != null) {
+                                trace.report(Errors.VARIABLE_WITH_REDUNDANT_INITIALIZER.on((JetNamedDeclaration) element, initializer, variableDescriptor));
+                            }
+                        }
                     }
 
                 }
@@ -570,8 +585,9 @@ public class JetFlowInformationProvider {
     }
 
     private static enum VariableStatus { 
-        READ(2),
+        READ(3),
-        WRITTEN(1),
+        WRITTEN(2),
+        ONLY_WRITTEN(1),
         UNUSED(0);
         
         private int importance;

compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/Errors.java

@@ -154,6 +154,7 @@ public interface Errors {
     UnusedElementDiagnosticFactory<JetProperty, VariableDescriptor> UNUSED_VARIABLE = UnusedElementDiagnosticFactory.create(WARNING, "Variable ''{0}'' is never used", NAME);
     UnusedElementDiagnosticFactory<JetParameter, VariableDescriptor> UNUSED_PARAMETER = UnusedElementDiagnosticFactory.create(WARNING, "Parameter ''{0}'' is never used", NAME);
     UnusedElementDiagnosticFactory<JetNamedDeclaration, DeclarationDescriptor> ASSIGNED_BUT_NEVER_ACCESSED_VARIABLE = UnusedElementDiagnosticFactory.create(WARNING, "Variable ''{0}'' is assigned but never accessed", NAME);
+    PsiElementOnlyDiagnosticFactory1<JetNamedDeclaration, DeclarationDescriptor> VARIABLE_WITH_REDUNDANT_INITIALIZER = PsiElementOnlyDiagnosticFactory1.create(WARNING, "Variable ''{0}'' initializer is redundant", NAME);
     PsiElementOnlyDiagnosticFactory2<JetElement, JetElement, DeclarationDescriptor> UNUSED_VALUE = new PsiElementOnlyDiagnosticFactory2<JetElement, JetElement, DeclarationDescriptor>(WARNING, "The value ''{0}'' assigned to ''{1}'' is never used", NAME) {
         @Override
         protected String makeMessageForA(@NotNull JetElement element) {

compiler/frontend/src/org/jetbrains/jet/lang/psi/JetPsiUtil.java

@@ -103,17 +103,4 @@ public class JetPsiUtil {
             return unquoteIdentifier(quoted);
         }
     }
-
-    public static boolean isLocal(@NotNull JetElement element) {
-        JetClassOrObject classOrObject = PsiTreeUtil.getParentOfType(element, JetClassOrObject.class);
-        JetDeclarationWithBody function = PsiTreeUtil.getParentOfType(element, JetDeclarationWithBody.class);
-        if (function != null && PsiTreeUtil.isAncestor(classOrObject, function, false)) {
-            return true;
-        }
-        if (classOrObject != null && PsiTreeUtil.isAncestor(function, classOrObject, false)) {
-            return false;
-        }
-        if (function != null) return true;
-        return false;
-    }
 }

compiler/testData/diagnostics/tests/BinaryCallsOnNullableValues.jet

@@ -11,7 +11,7 @@ class C() {
 }
 
 fun f(): Unit {
-  var <!ASSIGNED_BUT_NEVER_ACCESSED_VARIABLE!>x<!>: Int? = 1
+  var x: Int? = <!VARIABLE_WITH_REDUNDANT_INITIALIZER!>1<!>
   x = 1
   x <!UNSAFE_INFIX_CALL!>+<!> 1
   x <!UNSAFE_INFIX_CALL!>plus<!> 1

compiler/testData/diagnostics/tests/FunctionReturnTypes.jet

@@ -18,7 +18,7 @@ fun bbb() {
   return <!TYPE_MISMATCH!>1<!>
 }
 
-fun foo(expr: StringBuilder): Int {
+fun foo(<!UNUSED_PARAMETER!>expr<!>: StringBuilder): Int {
   val c = 'a'
   when(c) {
     0.chr => throw Exception("zero")
@@ -211,4 +211,4 @@ fun testFunctionLiterals() {
         object A {}
     }
 
-}
+}

compiler/testData/diagnostics/tests/UninitializedOrReassignedVariables.jet

@@ -16,7 +16,7 @@ fun t1(b : Boolean) {
     }
     doSmth(<!UNINITIALIZED_VARIABLE!>u<!>)
 
-    var <!ASSIGNED_BUT_NEVER_ACCESSED_VARIABLE!>r<!>: String
+    var r: String
     if (b) {
         r = "s"
     }

compiler/testData/diagnostics/tests/UnreachableCode.jet

@@ -137,7 +137,7 @@ fun tf() : Int {
   <!UNREACHABLE_CODE!>return 1<!>
 }
 
-fun failtest(a : Int) : Int {
+fun failtest(<!UNUSED_PARAMETER!>a<!> : Int) : Int {
   if (fail() || <!UNREACHABLE_CODE!>true<!>) {
 
   }

compiler/testData/diagnostics/tests/UnusedVariables.jet

@@ -1,7 +1,7 @@
 namespace unused_variables
 
 fun testSimpleCases() {
-    var <!ASSIGNED_BUT_NEVER_ACCESSED_VARIABLE!>i<!> = 2
+    var i = <!VARIABLE_WITH_REDUNDANT_INITIALIZER!>2<!>
     i = <!UNUSED_VALUE!>34<!>
     i = 34
     doSmth(i)
@@ -62,7 +62,7 @@ class MyTest() {
     }
 
     fun testIf() {
-        var <!ASSIGNED_BUT_NEVER_ACCESSED_VARIABLE!>a<!> : Any
+        var a : Any
         if (1 < 2) {
             a = 23
         }

idea/testData/checker/BinaryCallsOnNullableValues.jet

@@ -11,7 +11,7 @@ class C() {
 }
 
 fun f(): Unit {
-  var <warning>x</warning>: Int? = 1
+  var x: Int? = <warning>1</warning>
   x = 1
   x <error>+</error> 1
   x <error>plus</error> 1

idea/testData/checker/FunctionReturnTypes.jet

@@ -13,7 +13,7 @@ fun bbb() {
   return <error>1</error>
 }
 
-fun foo(expr: StringBuilder): Int {
+fun foo(<warning>expr</warning>: StringBuilder): Int {
   val c = 'a'
   when(c) {
     0.chr => throw Exception("zero")

idea/testData/checker/UnreachableCode.jet

@@ -135,7 +135,7 @@ fun tf() : Int {
   <error>return 1</error>
 }
 
-fun failtest(a : Int) : Int {
+fun failtest(<warning>a</warning> : Int) : Int {
   if (fail() || <error>true</error>) {
 
   }